{"id":867,"date":"2020-04-20T08:09:26","date_gmt":"2020-04-20T06:09:26","guid":{"rendered":"http:\/\/www.graphene.ac\/?p=867"},"modified":"2020-04-20T08:09:26","modified_gmt":"2020-04-20T06:09:26","slug":"the-excellent-quality-of-boron-nitride-grown-at-atmospheric-pressure","status":"publish","type":"post","link":"https:\/\/www.graphene.ac\/index.php\/2020\/04\/20\/the-excellent-quality-of-boron-nitride-grown-at-atmospheric-pressure\/","title":{"rendered":"The excellent quality of boron-nitride grown at atmospheric pressure"},"content":{"rendered":"\n

With what could be a step forward towards large-scale high-performance graphene electronics, a team of German and French scientists has demonstrated the excellent quality of monoisotopic hexagonal boron nitride grown at atmospheric pressure by the group of James Edgar at Kansas State University. <\/p>\n\n\n\n\n\n\n\n

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Optical-microscope image of a crystal of hBN grown at atmospheric pressure. <\/figcaption><\/figure>\n\n\n\n

Hexagonal boron\nnitride (hBN) is the unsung hero of graphene research. Indeed, much of the\nprogress of the last ten years has been enabled by the discovery that sandwiching\ngraphene between two hBN crystals can improve enormously the quality of\ngraphene devices. This has opened the door to a series of exciting\ndevelopments, including the discoveries of exotic effects such as magic-angle\nsuperconductivity and proof-of-concept demonstrations of sensors with\nunrivalled sensitivity. <\/p>\n\n\n\n

Up to now, the best\nand by far most widely used hBN crystals come from the laboratory of Takashi\nTaniguchi and Kenji Watanabe at the National Institute of Material Science in\nTsukuba, Japan. These crystals are grown using a process based on high\ntemperature (more than 1500\u00b0C) and extremely high pressure (more than 40.000\ntimes the atmospheric pressure). \u201cThe contribution of Taniguchi and Watanabe to\ngraphene research is invaluable\u201d, says Christoph Stampfer from RWTH Aachen\nUniversity. \u201cThey provide hundreds of labs around the world with ultra-pure hBN\nat no charge. Without their contribution, a lot of what we are doing today\nwould not be possible.\u201d<\/p>\n\n\n\n

The main limitations of\nthe hBN grown by Taniguchi and Watanabe are the crystal size, which is limited\nto a few 100 \u00b5m, and the complexity of the growth process. If this is good for\nfundamental research, it is a no-go in terms of scalability.  \u201cI\u2019ve been very excited when James Edgar\nproposed us to test the quality of his hBN\u201d, says Stampfer, \u201cas his growth\nmethod is in principle suitable for large-scale production\u201d. Edgar\u2019s method for\ngrowing hBN at atmospheric pressure is indeed much simpler and cheaper than the\none of the Japanese team. Furthermore, it also allows controlling the isotopic\nconcentration.  <\/p>\n\n\n\n

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One of the hBN crystals produced by Edgar’s group<\/figcaption><\/figure>\n\n\n\n

\u201cThe hBN crystals we received from Edgar\u2019s group were the largest I\u2019ve ever seen\u201d, says Jens Sonntag, a PhD student in Stampfer\u2019s group, \u201cand they were all based either on isotopically pure 10<\/sup>B or 11<\/sup>B\u201d. Sonntag tested the quality of the flakes first via confocal Raman spectroscopy and then, in a collaboration with the group of Annick Loiseau at ONERA-CNRS, via luminescence measurements. Both types of measurements indicated high isotope-purity and high crystal-quality. However, the strongest evidence of the high quality of Edgar\u2019s hBN came from the transport measurements performed on devices based on graphene sandwiched between monoisotopic hBN. In this type of experiment, the graphene sheet acts as a sensitive detector for disorder in the hBN. The performance of the devices based on monoisotopic hBN turned out to be absolutely equivalent to the one of state-of-the-art devices based on hBN produced by Taniguchi and Watanabe, if not slightly better.<\/p>\n\n\n\n

\u201cThis is a clear indication of the very high quality of the hBN crystals we received from Edgar\u2019s group\u201d, says Stampfer. \u201cThis is great news for the whole graphene community, because it shows that it is in principle possible to produce high-quality hBN on large scale, bringing us one step closer to real applications based on high-performance graphene electronics. And furthermore, the possibility of controlling the isotopic concentration of the crystals opens the door to experiments that were not possible before.\u201d This research has been published open-access on 2D Materials.<\/em><\/p>\n\n\n\n

Bibliographic info:
Excellent electronic transport in heterostructures of graphene and monoisotopic boron-nitride grown at atmospheric pressure
<\/em>J. Sonntag, J. Li, A. Plaud, A. Loiseau, J. Barjon, J. H. Edgar, C. Stampfer,
2D Materials<\/em> (2020, advanced on-line publication)
DOI: https:\/\/doi.org\/10.1088\/2053-1583\/ab89e5<\/a><\/p>\n\n\n\n

Contact:
Jens Sonntag
RWTH Aachen University,
II Institute of Physics
52074 Aachen (Germany)
email: sonntag@physik.rwth-aachen.de<\/p>\n","protected":false},"excerpt":{"rendered":"

With what could be a step forward towards large-scale high-performance graphene electronics, a team of German and French scientists has demonstrated the excellent quality of monoisotopic hexagonal boron nitride grown at atmospheric pressure by the group of James Edgar at Kansas State University.<\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[19,20,21],"class_list":["post-867","post","type-post","status-publish","format-standard","hentry","category-allgemein","tag-high-quality-hbn","tag-james-edgar","tag-monoisotopic-hbn"],"_links":{"self":[{"href":"https:\/\/www.graphene.ac\/index.php\/wp-json\/wp\/v2\/posts\/867","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.graphene.ac\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.graphene.ac\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.graphene.ac\/index.php\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/www.graphene.ac\/index.php\/wp-json\/wp\/v2\/comments?post=867"}],"version-history":[{"count":4,"href":"https:\/\/www.graphene.ac\/index.php\/wp-json\/wp\/v2\/posts\/867\/revisions"}],"predecessor-version":[{"id":873,"href":"https:\/\/www.graphene.ac\/index.php\/wp-json\/wp\/v2\/posts\/867\/revisions\/873"}],"wp:attachment":[{"href":"https:\/\/www.graphene.ac\/index.php\/wp-json\/wp\/v2\/media?parent=867"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.graphene.ac\/index.php\/wp-json\/wp\/v2\/categories?post=867"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.graphene.ac\/index.php\/wp-json\/wp\/v2\/tags?post=867"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}